This invention relates to a portable instrument and method for phonocephalography, and more particularly relates to an ausculative device and method for passively, non-invasively monitoring sounds from the surface and cavities of the head of the patient, and where desired, correlating such sounds with a person's electrocardiograph (ECG).
Oscultation in medical practice has undergone considerable progress since development of the mono-aural stethoscope. Phonocephalography is a new term introduced for the systematic oscultation, amplification and recording of sounds from the surface and cavities of the head. Hissing, pulsating or clicking sounds can be detected by phonocephalography. Audible sounds in these cases can be divided into pulsating vascular and clicking mascular tinnitus. Pulsating vascular tinnitus has fixed frequency, synchronous with the pulse and is not affected by swallowing or opening the mouth widely. Such tinnitus will change in character by compression of the carotids. Clicking tinnitus however has a variable frequency, asynchronous with the pulse. Its character will not change on compression of the carotids, but will change on swallowing or opening the mouth. For this reason, it is desirable to correlate a patient's ECG with audible sounds from the surface and cavities of the head. For instance different sounds of patients with red tumour complaining of tinnitus, patients with hypertension complaining of tinnitus, and patients with palatal myoclonus, can be identified and recorded all in correlation with ECG. Also aneurysmal dilation in a major vessel, e.g. the carotid artery, can be detected by audible sounds from the ear and correlated with the ECG. Moreover patients with carotid cavernous fistula can be detected. As far as is known by the applicant, there is no previous unitary phonocelographic device for obtaining information of the type in question. Such information in the past has been recorded by combining different and several pieces of equipment together such as microphones, audio frequency spectrometers, sound recorders, etc.
It should be noted that there are substantial differences between a phonocephalographic device such as that described in the present application and echocephalographic devices which are described in patents such as Canadian Pat. No. 973,632 of Hudson, et. al., issued Aug. 26, 1975; Canadian Pat. No. 970,462 of J. B. Williams, issued July 1, 1975. A phonocephalographic device is intended to record audible sounds from the head cavities (the ear for example)-sounds such as hissing, tinnitus, for example. Echocephalographic devices however are concerned with brain waves and use ultrasonic techniques which involve transmitting signals and recording echoes reflected from the brain. Thus the information as well as the type of signals received by these two types of devices are substantially different in nature and operation.
U.S. Pat. No. 4,008,711 of Olinger, et. al., issued Feb. 22, 1977, describes a device which monitors characteristic sounds emanated externally from the head by intracranial aneurysms. The device in question uses a microphone for picking up characteristic sound waves through a patient's closed eye lid, converting them into electric signals which are filtered, amplified, filtered again and recorded on one channel of a magnetic tape and correlated with audible heart signals which are recorded on another channel of the tape.
Other patents, of general background interest, are U.S. Pat. No. 3,990,435 of Murphy, issued Nov. 9, 1976; U.S. Pat. No. 3,653,373 of Batterman, issued Apr. 4, 1972 and U.S. Pat. No. 3,181,528 of Brackin, issued May 4, 1965.
It is an object of the present invention to provide a device for the monitoring and diagnosis of sounds from the surface and cavities of the head which will enable simple, passive, non-invasive cerebrial angiology. It is a further object of the present invention to provide a portable unitary instrument which will serve such a purpose. It is a further object of the present invention to provide a device which will enable correlative monitoring and recording of such sounds with a patient's ECG. These and other objects of the invention will be understood from the following description of the invention.